Author/Authors :
Seki، نويسنده , , Masahiko and Furutani، نويسنده , , Toshiyuki and Imashiro، نويسنده , , Ritsuo and Kuroda، نويسنده , , Tooru and Yamanaka، نويسنده , , Takeshi and Harada، نويسنده , , Naoyuki and Arakawa، نويسنده , , Hiroaki and Kusama، نويسنده , , Mari and Hashiyama، نويسنده , , Tomiki، نويسنده ,
Abstract :
A practical synthesis of methyl (2R,3S)-3-(4-methoxyphenyl)glycidate (−)-2a, a key intermediate for diltiazem (3), was described. Treatment of methyl (E)-4-methoxycinnamate (E)-1a with chiral dioxirane, generated in situ from a catalytic amount of an 11-membered C2-symmetric binaphthyl ketone 7a, provided (−)-2a in 78% ee and 89% yield. The crude mixture of (−)-2a and 7a was efficiently separated by the use of novel equipment performing continuous dissolution and crystallization to furnish the optically pure (−)-2a (>99% ee) and recovery of 7a in 64 and 88% yields, respectively.
Keywords :
asymmetric synthesis , epoxides , epoxidation , crystallization , Catalysts
